Assemblies exist today having bodies, some of which are heated and some of which are cooled. In many such assemblies it is desirable to minimize or limit the temperature of the heated bodies. By linking the bodies, heat can be conducted from the heated bodies to the cooled bodies with the result that the temperature of the heated bodies is reduced. Very effective thermal linkage will tend to make the cooled bodies nearly the same temperature as the heated bodies. The higher temperature of the cooled bodies generally increases their ability to dissipate heat, increasing the amount of heating the heated element can absorb without exceeding a temperature limit. From this it is clear that very effective thermal linkage is desirable. In general, a very effective thermal linkage places the heated and cooled bodies in close proximity and makes a complete thermal connection with a high-conductivity medium. Solder is an example of such a medium. It completely fills even a small gap between bodies and conducts heat very well. Solder also firmly connects the heated body to the cooled body. While this connection is desirable in order to consolidate the assembly it can also lead to a problem in the instance when two bodies (heated and cooled) tend to expand different amounts in operation. This may occur, for instance, if one body has a different coefficient of thermal expansion than the other. In the case of differential expansion, linkage between the two bodies will tend to compress the body of greater expansion across the surface of the interface. The body of lesser expansion will be tensioned, also across the surface of the interface. In some cases, the compression or tension stresses that arise may exceed the strength of one or both of the bodies, leading to undesirable performance of the assembly. Solder may be replaced with a non-rigid, highly-conductive paste. This eliminates the mutually induced stresses as the two bodies are not rigidly joined but requires additional components to connect the bodies together into an assembly. Such components add complexity and take up space, undesirable characteristics in some applications. Solder may also be replaced with a thermal adhesive. This provides the mechanical connection between the bodies, but generally provides substantially reduced thermal conductivity when compared to solder. Reduced conductivity leads to reduced heating capacity and/or higher temperature on the heated body or the need for a larger cooling capacity in the cooled body. This is undesirable in many applications.
An assembly having bodies of different thermal expansion rates and/or method of use is needed to decrease one or more problems associated with one or more of the existing assemblies and/or methods.